Server racks accommodate individual servers. Typically, the server rack includes two opposite side plates and two guide rails extending from an inner sides of each of the two side plates. The server is placed on the guide rail and installed in the server rack. The guide rail extends from a front end of the side plate to a rear end of the side plate and a distance between the two side plates is equal to a width of the server. When the server is placed on the slide rail, opposite ends of the server should be simultaneously placed between the two opposite side plates, which can be inconvenient when installing the server. Therefore, there is room for improvement within the art.